After following a liveblog of the presentation where Google announced Ice Cream Sandwich, one of the more interesting features announced was the ability to unlock your phone with your face. As in, the front facing camera is able to determine if the person in front of the camera is the owner of the phone.

What is the rate of false positives and false negatives for this feature? Can it be fooled by a photograph of the owner of the device? If it fails to unlock automatically, is there a fallback password/pin mechanism to unlock the device?

3 Answers
3

False negatives are rare in my experience. I did try to take a picture of myself with another phone and point the face unlock at the photo on the screen and that unlocked it. So it's not secure at all.

If it fails to unlock automatically, is there a fallback password/pin mechanism to unlock the device?

The ICS' config screen says it's for low security situation. It shouldn't be used for cases where you have sensitive information, and more for the casual user that uses their phones for personal photos; not the type who carries their company's next secret world domination plan. While face unlock is a gimmick, it's a cool gimmick nevertheless, and I'm sure it will be used by the casual users who values convenience more than security, as it is basically an automatic unlock for them.

If it fails to unlock automatically, is there a fallback password/pin
mechanism to unlock the device?

Not sure about that; but all stock unlock mechanism has a fallback to unlock using your Google Account username and password. I don't see why they wouldn't do that with face recognition.